Container-handling vehicle

ABSTRACT

A container-handling vehicle for picking up storage containers from a three-dimensional grid of an underlying storage system includes a vehicle body and at least one lifting device. The lifting device includes a lifting shaft assembly including a lifting shaft and at least one motor for rotating the lifting shaft, a lifting frame for releasably connecting a storage container, and a first pair of lifting bands and a second pair of lifting bands connecting the lifting shaft to the lifting frame. The lifting shaft includes a first end section and a second end section. Each lifting band has a first end and a second end connected to the lifting shaft and a corresponding lifting band connector on the lifting frame, respectively. Each pair of lifting bands has a first lifting band connected at the first end section of the lifting shaft and a second lifting band connected at the second end section of the lifting shaft. The first pair of lifting bands extends in a substantially horizontal direction from the lifting shaft towards a band guiding assembly, the band guiding assembly is arranged to change the direction of the first pair of lifting bands to extend in a vertical direction. The second pair of lifting bands extends in a vertical direction from the lifting shaft at the side of the lifting shaft facing away from the band guiding assembly, and the connections between the first ends of the first pair of lifting bands and the lifting shaft is staggered by 75-105 degrees relative the connections between the first ends of the second pair of lifting bands and the lifting shaft.

TECHNICAL FIELD

The present invention relates to a container handling vehicle and anautomated storage and retrieval system comprising the container handlingvehicle.

BACKGROUND AND PRIOR ART

Storage systems comprising a three-dimensional storage grid structure,within which storage containers/bins are stacked on top of each other,are well known.

FIG. 1 discloses a framework structure of a typical prior art automatedstorage and retrieval system 1 and FIGS. 2a and 2b disclose knowncontainer-handling vehicles of such a system. The storage system isdisclosed in detail in for instance NO317366 and WO 2014/090684 A1.

The framework structure comprises a plurality of uprightmembers/profiles 2 and a plurality of horizontal members 3, which aresupported by the upright members 2. The members 2, 3 may typically bemade of metal, e.g. extruded aluminium profiles.

The framework structure defines a storage grid 4 comprising multiplegrid columns 12 arranged in rows. A majority of the grid columns 12 arestorage columns 5 in which storage containers 6, also known ascontainers, are stacked one on top of another to form stacks 7. Eachstorage container 6 (or container for short) may typically hold aplurality of product items (not shown), and the product items within astorage container 6 may be identical, or may be of different producttypes depending on the application. The framework structure guardsagainst horizontal movement of the stacks 7 of storage containers 6, andguides vertical movement of the containers 6, but does normally nototherwise support the storage containers 6 when stacked.

The upper horizontal members 3 comprise a rail system 8 arranged in agrid pattern across the top of the grid columns 12, on which rail system8 a plurality of container-handling vehicles 9 are operated to raisestorage containers 6 from and lower storage containers 6 into thestorage columns 5, and also to transport the storage containers 6 abovethe storage columns 5. The rail system 8 comprises a first set ofparallel rails 10 arranged to guide movement of the container-handlingvehicles 9 in a first direction X across the top of the frame structure1, and a second set of parallel rails 11 arranged perpendicular to thefirst set of rails 10 to guide movement of the container-handlingvehicles 9 in a second direction Y, which is perpendicular to the firstdirection X, see FIG. 3. In this way, the rail system 8 defines an upperend of the storage columns 5, above which the container-handlingvehicles 9 can move laterally above the storage columns 5, i.e. in aplane, which is parallel to the horizontal X-Y plane.

Each container-handling vehicle 9 comprises a vehicle body 13 and firstand second sets of wheels 14, 15 which enable the lateral movement ofthe container-handling vehicle 9, i.e. the movement in the X and Ydirections. In FIG. 2, two wheels in each set are visible. The first setof wheels 14 is arranged to engage with two adjacent rails of the firstset 10 of rails, and the second set of wheels 15 arranged to engage withtwo adjacent rails of the second set 11 of rails. One of the set ofwheels 14, 15 can be lifted and lowered, so that the first set of wheels14 and/or the second set of wheels 15 can be engaged with theirrespective set of rails 10, 11 at any one time.

Each container-handling vehicle 9 also comprises a lifting device 18(not shown in FIGS. 1 and 2 a, but visible in FIG. 2b ) for verticaltransportation of storage containers 6, e.g. raising a storage container6 from and lowering a storage container 6 into a storage column 5. Thelifting device 18 comprises a lifting frame (not shown in FIG. 2a , butsimilar to the one shown in FIG. 2b labelled 17) which is adapted toengage a storage container 6, which lifting frame can be lowered fromthe vehicle body 12 so that the position of the lifting frame withrespect to the vehicle body 12 can be adjusted in a third direction Z,which is orthogonal the first direction X and the second direction Y.

Conventionally, and for the purpose of this application, Z=1 identifiesthe uppermost layer of the grid 4, i.e. the layer immediately below therail system 8 (in the present application, the rail system 8 is termedthe top level of the grid), Z=2 is the second layer below the railsystem 8, Z=3 is the third layer etc. In the embodiment disclosed inFIG. 1, Z=8 identifies the lowermost, bottom layer of the grid 4.Consequently, as an example and using the Cartesian coordinate system X,Y, Z indicated in FIG. 1, the storage container identified as 6′ in FIG.1 can be said to occupy grid location or cell X=10, Y=2, Z=3. Thecontainer-handling vehicles 9 can be said to travel in layer Z=0 andeach grid column 12 can be identified by its X and Y coordinates.

Each container-handling vehicle 9 comprises a storage compartment orspace for receiving and stowing a storage container 6 when transportingthe storage container 6 across the grid 4. The storage space maycomprise a cavity 21 arranged centrally within the vehicle body 13, e.g.as is described in WO2014/090684A1, the contents of which areincorporated herein by reference.

Alternatively, the container-handling vehicles may have a cantileverconstruction, as is described in NO317366, the contents of which arealso incorporated herein by reference.

The container-handling vehicles 9 may have a footprint F, i.e. ahorizontal periphery in the X and Y directions (see FIG. 4), which isgenerally equal to the lateral or horizontal extent of a grid column 12,i.e. the periphery/circumference of a grid column 12 in the X and Ydirections, e.g. as described in WO2015/193278A1, the contents of whichare incorporated herein by reference. Alternatively, thecontainer-handling vehicles 9 may have a footprint which is larger thanthe lateral extent of a grid column 12, e.g. a footprint approximatelytwice the lateral extent as disclosed in WO2014/090684A1.

The rail system 8 may be a single-track system, as shown in FIG. 3.Preferably, the rail system 8 is a double-track system, as shown in FIG.4, thus allowing a container-handling vehicle 9 having a footprint Fgenerally corresponding to the lateral extent of a grid column 12 totravel along a row of grid columns in either an X or Y direction even ifanother container-handling vehicle 9 is positioned above a grid column12 adjacent to that row.

In a storage grid, a majority of the grid columns 12 are storage columns5, i.e. grid columns where storage containers are stored in stacks.However, a grid normally has at least one grid column 12 which is usednot for storing storage containers, but which comprises a location wherethe container-handling vehicles can drop off and/or pick up storagecontainers so that they can be transported to an access station wherethe storage containers 6 can be accessed from outside of the grid ortransferred out of or into the grid, i.e. a container handling station.Within the art, such a location is normally referred to as a “port” andthe grid column in which the port is located may be referred to as aport column.

The grid 4 in FIG. 1 comprises two port columns 19 and 20. The firstport column 19 may for example be a dedicated drop-off port column wherethe container-handling vehicles 9 can drop off storage containers to betransported to an access or a transfer station (not shown), and thesecond port 20 column may be a dedicated pick-up port column where thecontainer-handling vehicles 9 can pick up storage containers that havebeen transported to the grid 4 from an access or a transfer station.

For monitoring and controlling the automated storage and retrievalsystem, e.g. monitoring and controlling the location of respectivestorage containers within the grid 4, the content of each storagecontainer 6 and the movement of the container-handling vehicles 9 sothat a desired storage container can be delivered to the desiredlocation at the desired time without the container-handling vehicles 9colliding with each other, the automated storage and retrieval systemcomprises a control system, which typically is computerised andcomprises a database for keeping track of the storage containers.

When a storage container 6 stored in the grid 4 disclosed in FIG. 1 isto be accessed, one of the container-handling vehicles 9 is instructedto retrieve the target storage container from its position in the grid 4and transport it to the drop-off port 19. This operation involves movingthe container-handling vehicle 9 to a grid location above the storagecolumn 5 in which the target storage container is positioned, retrievingthe storage container 6 from the storage column 5 using thecontainer-handling vehicle's lifting device (not shown, being internallyarranged in a central cavity of the vehicle, but similar to the liftingdevice 18 of the second prior art vehicle of FIG. 2b ), and transportingthe storage container to the drop-off port 19. A second prior artvehicle 9 is shown in FIG. 2b to better illustrate the general design ofthe lifting device. Details of the second vehicle 9 are described in theNorwegian patent NO317366. The lifting devices 18 of both prior artvehicles 9 comprise a set of lifting bands 16 extending in a verticaldirection and connected close to the corners of a lifting frame 17 (mayalso be termed a gripping device) for releasable connection to a storagecontainer. The lifting frame 17 features container connecting elements24 for releasably connecting to a storage container, and guiding pins30.

To raise or lower the lifting frame 17 (and optionally a connectedstorage container 6), the lifting bands 16 are connected to a band driveassembly. In the band drive assembly, the lifting bands 16 are commonlyspooled on/off at least two rotating lifting shafts or reels (not shown)arranged in the container-handling vehicle, wherein the lifting shaftsare further connected via belts/chains to at least one common rotorshaft providing synchronized rotational movement to the at least twolifting shafts. Various designs of lifting shafts are described in forinstance WO2015/193278 A1 and WO2017/129384.

To obtain a correct length of all the lifting bands 16 relative thelifting frame, i.e. such that the lifting frame 17 is kept horizontalduring operation, the length of the lifting bands must be adjusted bothinitially, as well as at various service intervals, since they tend toelongate slightly during use. In the prior art lifting devices, thelifting bands are commonly connected and spooled onto separate reelsarranged at an upper level within the container-handling vehicle 9. Toadjust a lifting band, the corresponding reel may be disconnected from arotational shaft and the lifting band adjusted by free rotation of thereel relative the rotational shaft. The reel is subsequently fastened tothe rotational shaft when the lifting band has the desired length. Toobtain access to the separate reels, a service person is required toremove at least some of the bodywork covering the vehicle body 13 orenter the cramped interior of the vehicle.

Most prior art container-handling vehicles having a central cavity forreceiving a storage bin, as in FIG. 2a , features a lifting device 18having a lifting band drive assembly comprising at least one rotorshaft, centrally arranged in an upper section of the vehicle andconnected to a lifting motor. In addition to the centrally arrangedrotor shaft, such lifting devices comprise an assembly of secondaryshafts and/or sheaves onto which the lifting bands are spooled on andoff. The secondary shafts and/or sheaves are rotated by being connectedto the centrally arranged rotor shaft via belts/chains, and are arrangedat the corners of the central cavity to provide the required positioningof the lifting bands 16 relative the lifting frame 17. Having such anassembly of multiple movable parts is not an optimal solution since thelifting devices are relatively service intensive, noisy and occupies alarge volume inside the robot.

A container-handling vehicle featuring a centrally arranged rotatablelifting shaft, onto which the lifting bands are spooled, is disclosed inWO2017/129384 A1.

In view of the above, it is desirable to provide a container-handlingvehicle, and an automated storage and retrieval system comprising saidcontainer-handling vehicle, wherein the disadvantages of the prior artlifting devices are avoided or at least mitigated.

SUMMARY OF THE INVENTION

The present invention is defined by the attached claims and in thefollowing:

In a first aspect, the present invention provides a container-handlingvehicle for picking up storage containers from a three-dimensional gridof an underlying storage system, comprising a vehicle body and at leastone lifting device, wherein the lifting device comprises a lifting shaftassembly comprising a lifting shaft and at least one motor for rotatingthe lifting shaft, a lifting frame for releasably connecting a storagecontainer, and a first pair of lifting bands and a second pair oflifting bands connecting the lifting shaft to the lifting frame, wherein

-   -   the lifting shaft comprises a first end section and a second end        section;    -   each lifting band has a first end and a second end connected to        the lifting shaft and a corresponding lifting band connector on        the lifting frame, respectively;    -   each pair of lifting bands has a first lifting band connected at        the first end section of the lifting shaft and a second lifting        band connected at the second end section of the lifting shaft;    -   the first pair of lifting bands extends in a substantially        horizontal direction from the lifting shaft towards a band        guiding assembly, the band guiding assembly is arranged to        change the direction of the first pair of lifting bands to        extend in a vertical direction; and wherein        the second pair of lifting bands extends in a vertical direction        from the lifting shaft.

The first aspect may alternatively be defined as a container-handlingvehicle for picking up storage containers from a three-dimensional gridof an underlying storage system, comprising a vehicle body and at leastone lifting device, wherein the lifting device comprises a lifting banddrive assembly, comprising a lifting shaft assembly and a band guidingassembly, a lifting frame for releasably connecting a storage container,and a first pair of lifting bands and a second pair of lifting bandsconnecting the lifting shaft to the lifting frame, the lifting bandassembly comprises a lifting shaft and at least one motor for rotatingthe lifting shaft, wherein

-   -   the lifting shaft comprises a first end section and a second end        section;    -   each lifting band has a first end and a second end connected to        the lifting shaft and the lifting frame, respectively;    -   each pair of lifting bands has a first lifting band connected at        the first end section of the lifting shaft and a second lifting        band connected at the second end section of the lifting shaft;    -   the first pair of lifting bands extends in a substantially        horizontal direction from the lifting shaft towards the band        guiding assembly, the band guiding assembly is arranged to        change the direction of the first pair of lifting bands to        extend in a vertical direction; and wherein        the second pair of lifting bands extends in a vertical direction        from the lifting shaft.

When arranged in the vertical direction, i.e. extending vertically, thelifting bands are arranged at a horizontal distance from each othercorresponding to the horizontal distance between corresponding bandconnecting elements on the lifting frame.

By having the second pair of lifting bands extending vertically from thelifting shaft, the lifting device will occupy a minimal space inside therobot since no additional lifting band guiding is required.

In an embodiment of the container-handling vehicle, the band guidingassembly and the lifting shaft are arranged such that each lifting bandextends in a vertical direction at a horizontal position correspondingto the horizontal position of a corresponding lifting band connector onthe lifting frame.

In an embodiment of the container-handling vehicle, the band guidingassembly comprises a sheave for each lifting band of the first pair oflifting bands. The sheaves are arranged such that each lifting band ofthe first pair of lifting bands extends in a vertical direction at aposition directly above a corresponding lifting band connector on thelifting frame.

In an embodiment of the container-handling vehicle, the second pair oflifting bands extends in a vertical direction from the lifting shaft atthe side of the lifting shaft facing away from the band guidingassembly.

In an embodiment of the container-handling vehicle the lifting framecomprises four corner sections and a lifting band connector connected toone of the lifting bands is arranged at each corner section, wherein theband guiding assembly and the lifting shaft is spaced such that eachlifting band extends in a vertical direction at a horizontal positioncorresponding to the horizontal position of the lifting band connectorto which it is connected.

In an embodiment of the container-handling vehicle, at least three ofthe lifting band connectors are adjustable, such that the level of thecorresponding corner sections may be adjusted. Alternatively, such thatthe vertical distance between the corresponding corner sections and thelifting band drive assembly may be adjusted.

In an embodiment of the container-handling vehicle, the at least onemotor is a brushless DC motor comprising a stator element and a rotorelement, and the lifting shaft is connected to, or constitutes a partof, the rotor element.

In one embodiment of the container-handling vehicle, the at least onemotor is arranged between the first and the second end section of thelifting shaft, or arranged at the first or the second end section of thelifting shaft. This provides a lifting shaft assembly not requiring anypower transfer bands, and a minimum of parts.

In an embodiment of the container-handling vehicle, the connectionsbetween the first ends of the first pair of lifting bands and thelifting shaft is staggered/displaced by 75-105 degrees, preferably byabout 90 degrees, relative the connections between the first ends of thesecond pair of lifting bands and the lifting shaft. The connectionsbetween the first ends of the first pair of lifting bands and thelifting shaft have the same radial position relative a centreline of thelifting shaft. The connections between the first ends of the second pairof lifting bands and the lifting shaft have the same radial positionrelative a centreline of the lifting shaft. The radial position of theconnections between the first ends of the first pair of lifting bandsand the lifting shaft is displaced/staggered by 75-105 degrees,preferably about 90 degrees, relative the radial position of theconnections between the first ends of the second pair of lifting bandsand the lifting shaft. The connections between the first ends of thelifting bands, i.e. the first ends of the four lifting bandsconstituting the first and second pair of lifting bands, and the liftingshaft are arranged at different axial positions relative the liftingshaft.

In an embodiment of the container-handling vehicle, the lifting shaftassembly comprises at least one electrical insulating element arrangedsuch that the lifting bands connected at the first end section iselectrically insulated from the lifting bands connected at the secondend section, i.e. such that the lifting bands connected at the first endsection may have an electric potential different from the lifting bandsconnected at the second end section.

By electrically insulating the lifting bands connected at the first endsection from the lifting bands connected at the second end section, thelifting bands may for instance be used to control the releasableconnection of the lifting frame to a storage container, while at thesame time having the lifting bands connected to a common lifting shaft.

In an embodiment of the container-handling vehicle, a dual band reel isarranged at each of the first end section and the second end section,each dual band reel is connected to two separate lifting bands.

In an embodiment of the container-handling vehicle, each dual band reelcomprises a first and a second reel section. Each reel section featuringa reel band connector for connection to a first end of a lifting band.The first reel sections connected to the first pair of lifting bands andthe second reel sections connected to the second pair of lifting bands.In other words, each of the first reel sections is connected to one ofthe two lifting bands of the first pair of lifting bands, and each ofthe second reel sections is connected to one of the two lifting bands ofthe second pair of lifting bands. The reel band connectors of the firstreel sections are staggered by 75-105 degrees, preferably about 90degrees, relative the reel band connectors of the second reel sections.The reel band connectors of the first reel sections have the same radialposition relative a centreline of the lifting shaft. The reel bandconnectors of the second reel sections have the same radial positionrelative a centreline of the lifting shaft. The radial position of thereel band connectors of the first reel sections are staggered by 75-105degrees, preferably about 90 degrees, relative the radial position ofthe reel band connectors of the second reel sections.

In an embodiment of the container-handling vehicle, each of the dualband reels provides electrical contact between at least one of thelifting bands connected thereto and a control unit arranged in thecontainer-handling vehicle, such that electrical signals and/power maybe transferred from the control unit via the dual band reel to the atleast one lifting band.

In an embodiment of the container-handling vehicle, each dual band reelcomprises a slip ring for electrical signal transfer between a controlunit arranged in the container-handling vehicle and the lifting bandsvia a conducting brush in contact with the slip ring.

At least an outer layer of the dual band reel and the slip ring is madein an electrically conducting material, such as an aluminium alloy. Thedual band reel is preferably made as a single reel element comprisingthe slip ring. However, the dual band reel may also comprise twoseparate band reels and a slip ring provided the separate band reels andthe slip ring are in electrical contact.

In an embodiment, the container-handling vehicle comprises wheels formoving the vehicle above or on top of the three-dimensional grid.

In an embodiment, the container-handling vehicle comprises

-   -   a first set of wheels arranged at opposite sides of the vehicle        body (or arranged at opposite sides of a cavity of the vehicle        body), for moving the vehicle along a first direction on the        grid;    -   a second set of wheels arranged at opposite sides of the vehicle        body, for moving the vehicle along a second direction on the        grid, the second direction being perpendicular to the first        direction; and    -   the first set of wheels displaceable in a vertical direction        between a first position, wherein the first set of wheels allow        movement of the vehicle along the first direction, and a second        position, wherein the second set of wheels allow movement of the        vehicle along the second direction, wherein        the vehicle body surrounds a cavity, and the at least one        lifting device is connected at a top section of the cavity to        lift a storage container from the grid and into the cavity, such        that a bottom of the storage container is at a level above the        lowest level of the second set of wheels.

In an embodiment, the container-handling vehicle comprises at least twolifting devices. The at least two lifting devices may be adjacent.

In an embodiment, the container-handling vehicle comprises four liftingdevices.

In an embodiment, the cavity is for accommodating at least two adjacentstorage containers and at least two adjacent lifting devices.

In an embodiment of the container-handling vehicle, the cavity comprisesa first vertical side section and a second vertical side section, thevertical side sections being parallel and arranged on opposite sides ofthe cavity, and wherein the lifting shaft is arranged adjacent andparallel to the first vertical side section and the first pair oflifting bands extends in a substantially horizontal direction from thelifting shaft towards the second vertical side section. In a containerhandling vehicle comprising a cavity for accommodating a single storagecontainer, the band guiding assembly is preferably arranged close to thesecond vertical side section such that the first pair of lifting bandsextends in a vertical direction close to the second vertical sidesection.

In a second aspect, the present invention provides a storage systemcomprising a three-dimensional grid and at least one container-handlingvehicle according to any of the preceding claims, wherein the gridcomprises multiple storage columns, in which storage containers may bestored on top of one another in vertical stacks, and the containerhandling vehicle is operated on rails at a top level of the grid forretrieving storage containers from, and storing storage containers in,the storage columns, and for transporting the storage containershorizontally across the grid.

In a third aspect, the present invention provides a method of raising orlowering a storage container relative a container-handling vehiclehaving a lifting device, the lifting device comprising a lifting shaftand at least one motor for rotating the lifting shaft, a lifting framefor releasably connecting the storage container, and a first pair oflifting bands and a second pair of lifting bands connecting the liftingshaft to the lifting frame, the method comprising the steps of:

-   -   spooling the first pair of lifting bands on or off the lifting        shaft, the first pair of lifting bands extending in a        substantially horizontal direction from the lifting shaft; and        simultaneously    -   spooling the second pair of lifting bands on or off the lifting        shaft, the second pair of lifting bands extending in a vertical        direction from the lifting shaft,        such that a storage container connected to the lifting frame is        raised or lowered relative the container-handling vehicle.

In an embodiment, the method comprises the step of guiding the firstpair of lifting bands from the substantially horizontal direction to avertical direction.

The term “lifting band drive assembly” is in the present inventionintended to mean any assembly of at least one lifting shaft and anycombination of reels, sheaves and/or motor(s) suitable for spooling andhorizontal positioning of lifting bands, preferably four lifting bands,such that a lifting frame arranged below the lifting band assembly maybe raised/lowered in the vertical direction while kept in a horizontalplane.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the present invention will now be described indetail by way of example only and with reference to the followingdrawings:

FIG. 1 is a perspective side view of a prior art storage and retrievalsystem.

FIGS. 2a and 2b depict two different prior art container handlingvehicles.

FIGS. 3 and 4 are top side schematic views of two types of rail systemsfor use in the storage system in FIG. 1.

FIG. 5 is a perspective side view of an exemplary embodiment of acontainer-handling vehicle according to the invention.

FIG. 6a is a side view of the container-handling vehicle in FIG. 5.

FIG. 6b is a top view of the container-handling vehicle in FIG. 5.

FIG. 7a is a sectional side view of a portion of the container-handlingvehicle in FIG. 5.

FIG. 7b is an enlarged view of details shown in FIG. 7 a.

FIG. 8 is a perspective side view of a lifting frame of thecontainer-handling vehicle in FIGS. 5-7.

FIGS. 9a-9c are perspective, top and cross-sectional views of anadjustable band connector of the lifting frame in FIG. 8.

FIG. 10 is an exploded view of the lifting device of thecontainer-handling vehicle in FIG. 5.

FIG. 11 is a perspective side view of the lifting device of thecontainer-handling vehicle in FIG. 5.

FIG. 12 is a side view of the lifting shaft assembly of the liftingdevice in FIGS. 10 and 11.

FIG. 13 is a cross-sectional view of the lifting shaft assembly in FIG.12.

FIG. 14 is a side view of an alternative lifting shaft assembly for usein the lifting device in FIGS. 10 and 11.

FIG. 15 is a cross-sectional view of the lifting shaft assembly in FIG.14.

FIG. 16 is a perspective view from below of the lifting shaft assemblyin FIGS. 14 and 15.

FIG. 17 is a perspective view from above of the lifting shaft assemblyin FIGS. 14-16.

FIG. 18 is an exploded view of the lifting shaft assembly in FIGS.14-17.

FIG. 19 is a perspective view from below of a lifting device framecomprising the lifting shaft assembly in FIGS. 14-17.

FIG. 20 is a perspective side view of the lifting device frame in FIG.19 comprising lifting bands and a lifting frame.

FIG. 21 is a perspective side view of the lifting frame shown in FIG. 20with a top cover omitted.

FIG. 22 show two perspective side views of an adjustable lifting bandconnector of the lifting frame in FIG. 21.

FIG. 23 is a side view of a container-handling vehicle comprising alifting frame and lifting device as shown in FIG. 20.

FIG. 24 shows a side view and a cross-sectional view of an exemplarycontainer-handling vehicle according to the invention.

FIG. 25 is a perspective cross-sectional view of the container-handlingvehicle in FIG. 24.

FIG. 26 is an enlarged view of detail A shown in FIG. 24.

FIG. 27 is a perspective side view of yet an exemplary embodiment of acontainer-handling vehicle according to the invention.

FIG. 28 is a perspective view from below of the container-handlingvehicle in FIG. 27.

DETAILED DESCRIPTION OF THE INVENTION

In the following, embodiments of the invention will be discussed in moredetail by way of example only and with reference to the appendeddrawings. It should be understood, however, that the drawings are notintended to limit the invention to the subject-matter depicted in thedrawings.

As mentioned above, a disadvantage of the prior art lifting devices 18is the requirement of a lifting band drive assembly featuring aplurality of secondary shafts and/or sheaves, onto which the liftingbands 16 are spooled on and off, to provide the required positioning ofthe lifting bands relative the lifting frame. Further, to rotate thesecondary shafts and/or sheaves they are connected to a rotor shaft viabelts/chains.

An exemplary embodiment of a container-handling vehicle 9′ according tothe invention is shown in FIGS. 5, 6 a and 6 b. The main differentialfeature of the vehicle 9′ in view of the prior art vehicles 9, is theinventive lifting device 18′.

As described for the prior art vehicles 9, the container-handlingvehicle 9′ is suitable for picking up storage containers 6 from athree-dimensional grid 4 of an underlying storage system 1, see FIG. 1.The vehicle 9′ features a first set of wheels 14 arranged at oppositesides of the vehicle body 13, for moving the vehicle 9′ along a firstdirection X on the grid 4, and a second set of wheels 15 arranged atopposite sides of the vehicle body 13, for moving the vehicle 9′ along asecond direction Y on the grid 4, the second direction Y beingperpendicular to the first direction X. The wheels are driven by asuitable wheel drive (not shown). Examples of suitable wheel drives arewell known in the prior art disclosed above. By use of a wheeldisplacement assembly 51, the first set of wheels may be displaced in avertical direction Z between a first position, wherein the first set ofwheels 14 allow movement of the vehicle 9′ along the first direction X,and a second position, wherein the second set of wheels 15 allowmovement of the vehicle 9′ along the second direction Y.

The vehicle body 13 surrounds a cavity 21 sized to accommodate a storagecontainer 6 suitable for a storage system as described above. A liftingdevice 18′ is connected at a top section of the cavity 21. The liftingdevice is arranged to lift/lower a storage container 6 from/to the grid4. When the storage container is accommodated within the cavity 21, thebottom of the storage container is at a level above the lowest level ofthe second set of wheels 15.

As shown in FIGS. 5 and 10, the lifting device 18′ comprises ahorizontal lifting shaft assembly 47 comprising a lifting shaft 22 andtwo electric motors 23 a, 23 b for rotating the lifting shaft 22, alifting frame 17 for releasable connection to a storage container 6, anda first and second pair of lifting bands 16 a,16 b. The lifting bands 16a,16 b connect the lifting shaft 22 to the lifting frame 17.

The lifting shaft 22 comprises a first end section 27 a and a second endsection 27 b interconnected via an intermediate shaft element 35.

Each lifting band 16 a,16 b has a first end and a second end connectedto the lifting shaft 22 and the lifting frame 17, respectively. Eachpair of lifting bands 16 a,16 b has a first lifting band connected atthe first end section 27 a of the lifting shaft and a second liftingband connected at the second end section 27 b of the lifting shaft. Thefirst pair of lifting bands 16 a extends in a substantially horizontaldirection from the lifting shaft 22 towards a pair of sheaves 31 (i.e. aband guiding assembly). The sheaves 31 are arranged to change thedirection of the first pair of lifting bands 16 a to extend in avertical direction. The second pair of lifting bands 16 b extends in avertical direction directly from the lifting shaft 22.

The lifting band drive assembly of the presently disclosedcontainer-handling vehicle 9′, or lifting device 18′, requires a minimumof separate parts, i.e. the lifting shaft assembly 47 and the pair ofsheaves 31, to achieve its function.

When extending in the vertical direction, the lifting bands 16 a,16 bare arranged at a horizontal distance from each other corresponding tothe horizontal distance between corresponding lifting band connectingelements 32 on the lifting frame 17.

By arranging the lifting shaft assembly 47 such that the second pair oflifting bands 16 b extends vertically from the lifting shaft towards thecorresponding band connecting elements 32 on the lifting frame 17, thelifting device 18′ will occupy a minimum of space inside the robot. Inother words, the required position and/or direction of the second pairof lifting bands 16 b is obtained without an additional band guidingassembly. Further, by using a minimum of rotational parts (i.e. only thelifting shaft 22 and the sheaves 31) and no gears, sprockets and/orchains (commonly used in prior art lifting devices to transferrotational movement from e.g. a motor to various shaft assemblies), thelifting device 18′ is significantly more silent than prior art liftingdevices. The latter is particularly important in a storage systemcomprising multiple container-handling vehicles.

Although the disclosed band guiding assembly comprises a pair of sheaves31, it may alternatively be replaced by any suitable means for changingthe direction of the first pair of lifting bands from a substantiallyhorizontal direction to the vertical direction, such as a rotationalshaft. In the container-handling vehicle 9′, each of the sheaves 31 isseparately connected to the vehicle body 13. However, depending on thespecific design and space requirements, they may alternatively bearranged having a common shaft 53 extending between opposite sides ofthe vehicle body 13, see FIG. 19.

As shown in FIG. 16, spring-loaded guide wheels 61 are arranged toensure correct travel and positioning of the lifting bands when spooledon/off the dual band reels 48 and when passing over the sheaves 31 ofthe band guiding assembly.

In the exemplary embodiment, the second pair of lifting bands 16 bextends in the vertical direction from the lifting shaft 22 at the sideof the lifting shaft facing away from the band guiding assembly 31. Inthis manner, the required horizontal position of the verticallyextending second pair of lifting bands 16 b, relative the correspondingband connecting elements of the lifting frame 17, is obtained whilekeeping the lifting device (and consequently the container-handlingvehicle) as compact as possible. In other words, the horizontal extentof the lifting device does not significantly exceed the horizontalperiphery of the lifting frame, which would be the case if the secondpair of lifting bands 16 b extended in the vertical direction from thelifting shaft 22 at the side of the lifting shaft facing the bandguiding assembly 31.

To provide secure spooling of the lifting bands onto the lifting shaft22, a dual band reel 48, see FIGS. 12 and 13, is arranged at each of theend sections 27 a,27 b. The dual band reel 48 comprises a first reelsections 48 a and a second reel section 48 b. Each reel section featuresa reel band connector 75 a,75 b for connecting two separate liftingbands, in this case a lifting band from each of the first and secondpair of lifting bands 16 a,16 b. In the lifting device 18′ (as well asthe lifting device 18″ described below) the two pairs of lifting bands16 a,16 b extend from the lifting shaft assembly 47 in two differentdirections, i.e. the first pair of lifting bands 16 a extends in asubstantially horizontal direction, while the second pair of liftingbands 16 b extend in a vertical direction. To obtain an identicaltravelling distance of all the lifting bands when the lifting shaft isrotated, it is important that all lifting bands have the same lengthspooled onto the dual band reels at all times. The thickness of thelifting bands is usually about 0.15 mm and the travelling length of alifting band per rotation of the lifting shaft (or dual band reel) isdependent on the number of layers of lifting band spooled onto the dualband reel. In the disclosed embodiments, this is obtained by having thetwo reel band connectors 75 a,75 b of each dual band reel 48 staggeredby about 90 degrees (depending on the length and thickness of thelifting bands, the staggering may be within the range of 75-105degrees). In other words, the two reel band connectors 75 a,75 b arearranged on their corresponding reel section at a positiondisplaced/staggered by about 90 degrees relative one another and thecentreline of the lifting shaft. Further, the dual band reels 48 arearranged such that the band connectors 75 a connecting the first pair oflifting bands have the same radial position (i.e. not staggered relativeeach other), and the band connectors 75 b connecting the second pair oflifting bands have the same radial position.

As discussed above, to obtain a correct length of all the lifting bands16 relative the lifting frame, i.e. such that the lifting frame 17 iskept horizontal during operation, the length of the lifting bands mustbe adjusted both initially, as well as at various service intervalssince they tend to elongate slightly during use. In the prior artlifting devices, the lifting bands are commonly connected and spooledonto separate reels arranged at an upper level within thecontainer-handling vehicle 9. To adjust a lifting band, thecorresponding reel may be disconnected from a rotational shaft and thelifting band adjusted by free rotation of the reel relative therotational shaft. The reel is subsequently fastened to the rotationalshaft when the lifting band has the desired length. To obtain access tothe separate reels, a service person is commonly required to remove atleast some of the bodywork covering the vehicle body 13 or enter thecramped interior of the cavity 21. A variant of the described prior artsolution may also be adapted for the exemplary embodiment, e.g. byreplacing each dual band reel with two separate band reels which mayindividually be released to allow free rotation relative to the liftingshaft 22 when the bands are to be adjusted. However, a more efficientand novel solution as described below is preferred.

In the exemplary embodiment, lifting band adjustment is obtained byusing a lifting frame 17 featuring adjustable lifting band connectors 32(or band connecting elements), see FIGS. 7-9. The lifting framecomprises four corner sections 36, a top side 37 and a bottom side 38.Four gripper elements 24 for interaction with a storage container arearranged at the bottom side 38 of the lifting frame 17. A vertical guidepin 30 and a vertically adjustable lifting band connector 32 arearranged at each corner section 36.

As shown in FIGS. 9a-9c each lifting band connector 32 comprises abracket 39 and a band connector hub 40. The bracket 39 is rigidlyconnected at the top side of the lifting frame 17. The band connectorhub 40 comprises a lifting band clamp 41 (i.e. a band fasteningassembly) and is adjustably connected to the bracket 39, such that theband connector hub 40 may be adjusted in a vertical direction relativethe bracket 39. The band connector hub 40 is connected to the bracket 39via an adjustment bolt 42 (i.e. an adjustment element) arranged suchthat rotation (i.e. actuation) of the adjustment bolt will move the bandconnector hub 40 in a vertical direction relative the bracket 39. Thebracket features a vertical recess/cut-out 43 and the band connector hub40 comprises an extension 44 arranged in the vertical recess. The recesscomprises two vertically opposite smooth bores 45 and the extensionfeatures a threaded bore 46 arranged in line with the smooth bores 45.By having the adjustment bolt 42 arranged in the smooth bores and thethreaded bore, rotation of the adjustment bolt 42 will move the bandconnector hub 40 in a vertical direction relative the bracket. Thus, thedistance between the lifting frame 17 and the vehicle body 13 may beadjusted such that the lifting frame is horizontal. The feature of beingable to adjust the lifting bands at the lifting frame is highlyadvantageous, since internal access to the body of thecontainer-handling vehicle is not required. Further, the lifting shaftassembly is simplified in that the dual band reels 48 upon which thelifting bands are spooled do not have to be releasably connected to thelifting shaft 22. The latter also entails that the lifting assembly, andany other systems present at an upper level within thecontainer-handling vehicle, may be constructed in a manner not having totake into consideration a required access to the reels. It is noted thatthe solution of having adjustable lifting band connectors on the liftingframe would be highly advantageous also in the prior artcontainer-handling vehicles.

Metal lifting bands may tear if subjected to unbalanced and high loads.To minimize the risk of unbalanced loads and tearing, the lifting bandconnector comprises a pivot point P allowing some movement of thelifting band connector in the vertical plane of the connected liftingband, i.e. the pivot point has a centre axis perpendicular to thevertical plane of the lifting band. In the lifting band connector 32,the pivot point P is obtained by a pivot connection 67 between thelifting band clamp 41 and the remainder of the band connector hub 40.

By use of the present lifting frame 17, as well as the lifting frame 17′shown in FIGS. 20-23, the lifting bands may be adjusted in an easy andtime efficient manner. When an adjustment is required (i.e. the liftingframe tilts slightly relative the horizontal plane; a situation that maycause the lifting frame getting stuck inside a storage column 12, seeFIG. 1), the following steps may be performed:

-   -   arranging the container-handling vehicle at a suitable location,        for instance at an empty grid column at the periphery of the        storage grid 4;    -   lowering the lifting frame out of the cavity of the        container-handling vehicle, such that a service person has        access to the lifting frame; and    -   adjusting the lifting band(s) by movement of the band connector        hub of the respective lifting band connector 32, such that the        lifting frame is in the horizontal plane. In the specific        lifting band connector disclosed in FIGS. 7-9, this step will        entail rotation of the respective adjustment bolt(s) (i.e. the        adjustment element(s)).

In some instances, when lowered out of the cavity, the lifting frame islowered to a base structure on which the frame is supported in thedesired horizontal position. When the lifting frame is kept horizontal,the lifting band(s) which has been elongated/stretched during use is nolonger tensioned, i.e. the elongated/stretched lifting band(s) has someslack relative the other lifting bands. The lifting band adjustment isthen easily performed by simply tensioning the slack lifting band(s) byuse of the respective adjustable lifting band connector 32.

In the exemplary embodiment, as well as in some prior artcontainer-handling vehicles, the lifting bands are made of metal(commonly a steel alloy) and are used to conduct signals and electricpower to end switch modules 29 and a control module 69 arranged on thelifting frame 17. The end switch modules 29 comprises spring-loaded pins68 (see FIG. 21) for detecting when the lifting frame is in contact witha storage container 6 and when the lifting frame is raised to itsuppermost level within the cavity. To avoid short-circuiting thesignal/electric power passing through the lifting bands, at least partsof the bracket 39 is made in a non-conducting material, such as asuitable plastic or composite material, such that the lifting bands(i.e. a lifting band from each of the dual band reels 48) are only inelectric contact (via wires 71) with the lifting frame 17 at the controlmodule 69. Thus, at least parts of the lifting band clamp 41 is made inan electrically conductive material, e.g. any suitable metal.

Each end switch module 29 is electrically connected (wires 72), via thecontrol module to two lifting band clamps 41 (or band connector hubs)having a different potential, such that signals/electric power may bereceived from, or sent to, a main control unit (not shown, but similarto the main control unit 58 in FIG. 16) inside the container-handlingvehicle.

The control module 69 is also connected to and controls gripper motors70 which drive the gripper elements 24.

To transfer signals and/or electric power from the main control unit,each dual band reel 48 features a slip ring 49 for electric signaltransfer between the main control unit and the lifting bands via aconducting brush 50 in contact with the slip ring 49, see FIG. 13. Thedual band reels are made in an electrically conducting material, such asa suitable metal. Although shown as a single reel, each dual band reelmay comprise to distinct reels, one for each lifting band, as long asthe two distinct reels are in electric contact with each other and theslip ring.

For illustrative purposes, the lifting device 18′ (i.e. the liftingshaft assembly 47, the lifting frame 17 and the two pairs of liftingbands) is shown in an exploded view in FIG. 10 and in a perspective viewisolated from the vehicle body 13 in FIG. 11.

In the lifting shaft assembly 47, the two electric motors 23 a, 23 b arebrushless DC (BLDC) electric motors, each comprising a stator 33, astator connecting element 55 and a rotor element 34, see FIGS. 12 and13. To transfer rotary motion from the rotor elements 34 a,34 b of theelectric motors to the lifting shaft 22 (i.e. the shaft made up of thefirst end section 27 a, the second end section 27 b and the intermediateshaft element 35), the rotor elements 34 a,34 b are interconnected viathe intermediate shaft element 35 and each rotor element is connected toa respective end section 27 a,27 b. The rotor elements, the end sectionsand the intermediate shaft element have a common centreline C. To allowspooling of all the lifting bands (i.e. both pairs of lifting bands 16a,16 b) onto a single lifting shaft 22, while at the same time beingable to use the lifting bands as conductors for signals/electric power,as described above, the dual band reels 48 (or the end sections 27 a,27b) must be electrically insulated from each other. In this manner thelifting bands connected to the dual band reel 48 at the first endsection 27 a may have a differential electric potential relative thelifting bands connected to the dual band reel 48 at the second endsection 27 b. In the lifting shaft assembly 47, this is achieved byhaving the intermediate shaft element 35 made in an electricallyinsulating material (i.e. providing an electrical insulating element),such as a suitable plastic/composite material.

The lifting shaft assembly 47 comprises a ball bearing element 52 oneach of the end sections 27 a,27 b for rotatable connection of the endsections to the body 13 of the container-handling vehicle. The statorconnecting element 55 of each stator 33 a,33 b comprises a motor bracket28 for rigid connection to the body 13 of the container-handling vehicleand a ball bearing 60 for rotary connection to the lifting shaft. Inthis manner, the lifting shaft 22 is rotatable relative the body 13,while the stators are kept stationary. To avoid short-circuiting via thevehicle body 13, the ball bearing elements 52 has a plastic housinginsulating the respective end sections from the vehicle body 13.Similarly, the stator connecting elements 55 are insulated from the endsections 27 a,27 b by the plastic housings 74 of the ball bearingelements 73 to avoid short circuiting via the motor brackets 28.

An alternative embodiment of a lifting shaft assembly 47′ is shown inFIGS. 14-18.

A differentiating feature of the alternative lifting shaft assembly 47′,in view of the lifting shaft assembly 47 described above, is theconstruction of the lifting shaft 22′ as a single element, i.e. thelifting shaft 22′ may be termed a unitary lifting shaft. In the liftingshaft assembly 47, the intermediate shaft element 35, interconnectingthe first end section 27 a and the second end section 27 b, is able toelectrically insulate the two end sections, and consequently the twodual band reels 48, by being made in an electrically insulatingmaterial. To obtain the same feature of electrically insulating the dualband reels 48, the alternative lifting assembly 47′ features asleeve-shaped element 54 made of electrically insulating material (i.e.an electrical insulating element) arranged between each of the first endsection 27 a and the second end section 27 b and the corresponding dualband reels 48 (alternatively, each dual band reel 48 may be defined ascomprising an inner section/element 54 in an electrically insulatingmaterial). An advantageous effect of insulating each dual band reel fromits respective end section is that the lifting shaft assembly 47′ is notrequired to be electrically insulated from the vehicle body 13 at itscontact points, e.g. ball bearings 52, see above.

The motor(s) 23 of the lifting shaft assembly 47′ features two stators33 a,33 b, two rotor elements 34 a,34 b and a stator connecting element55 being common for both stators 33 a,33 b. The stator connectingelement 55 comprises a motor bracket 28 for rigid connection to the body13 of the container-handling vehicle and ball bearings 60 for rotaryconnection to the lifting shaft 22′. A lift brake wheel 57 is arrangedat one end of the lifting shaft assembly 47′. To actuate the brakewheel, a cooperating brake actuator arm 59 is commonly connected to thevehicle body 13.

A lifting device 18″ based on the alternative lifting shaft assembly 47′is shown in FIGS. 19 and 20. In this specific embodiment, the liftingdevice 18″ is arranged in a frame 56. The frame 56 constitutes an upperpart of the vehicle body 13 of an assembled container handling vehicle9′, see FIG. 23.

The lifting frame 17′ of the lifting device 18″ has most of its featuresin common with the lifting frame disclosed in FIGS. 7-9, but comprisesan alternative type of adjustable lifting band connectors 32′, see FIGS.21 and 22. Each of the adjustable lifting band connectors 32′, see FIGS.21 and 22, comprises a bracket 39′ and a band connector hub 63,64. Apivot point P is obtained by having the bracket 39′ pivotally arrangedat an upper side of the lifting frame 17′ via a pivot connection 66 to aconnecting block 62 (or intermediate bracket element). The purpose ofthe pivot point P is described above in connection with the lifting bandconnector 32 in FIGS. 7-9. The band connector hub comprises a liftingband reel 63 and a locking bolt 64 (i.e. an adjustment element). Thelifting band reel features a connecting interface 65 for a lifting band(i.e. a band fastening assembly) and is rotatably connected to thebracket 39′. The rotational connection of the lifting band reel iscontrolled by the locking bolt 64. When the locking bolt 64 is tightenedthe lifting band reel 63 is prevented from rotating, and when thelocking bolt is loosened, rotation of the lifting band reel is allowed.By rotating the lifting band reel, the lifting band connected theretomay be spooled on/off such that the distance between the lifting frameand the vehicle body may be adjusted. An advantage of the lifting bandconnectors 32′ is that the vertical adjustment range is increased. Toavoid short-circuiting, at least parts of the lifting band connectors,such as the bracket 39′ or the connecting block 62, are made in anon-conducting material, such as a suitable plastic or compositematerial.

A container-handling vehicle featuring a frame 56 and lifting device 18′is shown in FIG. 23.

It is noted that in other embodiments, the lifting shaft assemblies47,47′ may comprise only one motor or more than two motors. This willdepend on the required torque of the lifting shaft 22,22′ as well as thetorque and size of current BLDC motors. For example, if the motor 23 aconnected to the first end section 27 a of the lifting shaft assembly 47was able to provide sufficient torque alone, the other motor 23 b couldbe replaced by an element simply connecting the second end section 27 band the intermediate shaft element 35. Various alternative solutionswould be obvious to the skilled person based on the teachings of thepresent disclosure. A common feature of all disclosed lifting shaftassemblies 47,47′ is that the at least one motor 23 a,23 b is arrangedbetween the first and second end section of the lifting shaft 22,22′ toensure a compact lifting shaft assembly.

Various types of brushless DC motors are known, including permanentmagnet synchronous motor (using permanent magnets) and switchedreluctance motors (does not use any permanent magnets).

The working principles of the permanent magnet synchronous brushless DCmotor is well known to the skilled person, e.g. as described inhttps://en.wikipedia.org/wiki/Brushless_DC_electric_motor, and typicallyuses one or more permanent magnets in the rotor and electromagnets onthe motor housing for the stator. A motor controller converts DC to AC.This design is mechanically simpler than that of brushed motors becauseit eliminates the complication of transferring power from outside themotor to the spinning rotor.

A further exemplary container-handling vehicle 9″ according to theinvention is shown in FIGS. 24-26. The vehicle features a lifting device(i.e. a lifting shaft assembly 47″, two pairs of lifting bands 16 a,16b, a lifting frame 17′ and a band guiding assembly) similar to thelifting devices 18′,18″ disclosed above. The main differentiatingfeature of this embodiment is that the lifting shaft assembly 47″ doesnot comprise a motor arranged between the two dual band reels 48 on thelifting shaft 22′. Instead, a motor 76 is connected at the end of theend section 27 b, see FIG. 24 (Section A-A). The band guiding assemblyis not shown but comprises two sheaves 31 arranged on a common shaft 53as shown in FIG. 19. Space for the motor 76 is provided by having avehicle body design comprising a side section in addition to the mainsection in which the lifting frame is arranged. The main section has afootprint similar to the footprint of the container-handling vehicle 9′in FIG. 5. An advantage of this solution is that it allows for a largerand stronger motor if needed. Further, the motor 76 may be any suitabletype of electric motor. Electric insulation of the two dual band reels48 is obtained as disclosed for the embodiment in FIG. 15. The liftingbands are connected to adjustable lifting band connectors 32′ on thelifting frame 17, similar to the connectors disclosed in FIGS. 21 and22.

Yet an exemplary container-handling vehicle 9′″ according to theinvention is shown in FIGS. 27-28. The vehicle features a lifting device(i.e. a lifting shaft assembly 47′, two pairs of lifting bands 16 a,16b, a lifting frame (not shown) and a band guiding assembly similar tothe lifting devices 18′,18″ disclosed above. The main differentiatingfeature of this embodiment in view of the container-handling vehicle inFIGS. 24-26 is that the motor 76′ of the lifting shaft assembly 47′ isarranged between the two dual band reels 48 on the lifting shaft 22′. Toallow room for a storage container in the cavity, the motor is arrangedin a substantially horizontal direction.

The lifting shaft assemblies 47-47′″ and the lifting frames 17,17′ aredisclosed in connection with a specific lifting band drive assembly47-47′″,31 and type of container-handling vehicle 9′,9″ having a cavityspaced to receive a single storage container. However, both the liftingshaft assemblies 47-47′ and the lifting frames 17,17′ may advantageouslybe used separately or in any combination in any type of lifting banddrive assembly or container-handling vehicle.

1. A container-handling vehicle for picking up storage containers from athree-dimensional grid of an underlying storage system, comprising avehicle body and at least one lifting device, wherein the lifting devicecomprises a lifting shaft assembly comprising a lifting shaft and atleast one motor for rotating the lifting shaft, a lifting frame forreleasably connecting a storage container, and a first pair of liftingbands and a second pair of lifting bands connecting the lifting shaft tothe lifting frame, wherein the lifting shaft comprises a first endsection and a second end section; wherein each lifting band has a firstend and a second end connected to the lifting shaft and a correspondinglifting band connector on the lifting frame, respectively; wherein eachpair of lifting bands has a first lifting band connected at the firstend section of the lifting shaft and a second lifting band connected atthe second end section of the lifting shaft; wherein the first pair oflifting bands extends in a substantially horizontal direction from thelifting shaft towards a band guiding assembly, the band guiding assemblyis arranged to change the direction of the first pair of lifting bandsto extend in a vertical direction; and wherein the second pair oflifting bands extends in a vertical direction from the lifting shaft atthe side of the lifting shaft facing away from the band guidingassembly, and the connections between the first ends of the first pairof lifting bands and the lifting shaft is staggered by 75-105 degreesrelative the connections between the first ends of the second pair oflifting bands and the lifting shaft.
 2. A container-handling vehicleaccording to claim 1, wherein the band guiding assembly and the liftingshaft are arranged such that each lifting band extends in a verticaldirection at a horizontal position corresponding to the horizontalposition of the corresponding lifting band connector on the liftingframe.
 3. A container-handling vehicle according to claim 1, wherein theband guiding assembly comprises a sheave for each lifting band of thefirst pair of lifting bands.
 4. (canceled)
 5. A container-handlingvehicle according to claim 1, wherein the lifting frame comprises fourcorner sections and a lifting band connector connected to one of thelifting bands is arranged at each corner section, wherein the bandguiding assembly and the lifting shaft is spaced such that each liftingband extends in a vertical direction at a horizontal positioncorresponding to the horizontal position of the lifting band connectorto which the lifting band is connected.
 6. A container-handling vehicleaccording to claim 1, wherein the at least one motor is a brushless DCmotor comprising a stator element and a rotor element, and the liftingshaft is connected to, or constitutes a part of, the rotor element.
 7. Acontainer-handling vehicle according to claim 6, wherein the at leastone motor is arranged between the first and the second end section ofthe lifting shaft.
 8. A container-handling vehicle according to claim 1,wherein the connections between the first ends of the first pair oflifting bands and the lifting shaft is staggered by about 90 degrees,relative the connections between the first ends of the second pair oflifting bands and the lifting shaft.
 9. A container-handling vehicleaccording to claim 1, wherein at least three of the lifting bandconnectors are adjustable, such that the level of the correspondingcorner sections may be adjusted.
 10. A container-handling vehicleaccording to claim 1, comprising: a first set of wheels arranged atopposite sides of the vehicle body, for moving the vehicle along a firstdirection on the grid; a second set of wheels arranged at opposite sidesof the vehicle body, for moving the vehicle along a second direction onthe grid, the second direction being perpendicular to the firstdirection; and the first set of wheels displaceable in a verticaldirection between a first position, wherein the first set of wheelsallow movement of the vehicle along the first direction, and a secondposition, wherein the second set of wheels allow movement of the vehiclealong the second direction, wherein the vehicle body surrounds a cavity,and the at least one lifting device is connected at a top section of thecavity to lift a storage container from the grid and into the cavity,such that a bottom of the storage container is at a level above thelowest level of the second set of wheels.
 11. A container-handlingvehicle according to claim 1, wherein the cavity comprises a firstvertical side section and a second vertical side section, the verticalside sections being parallel and arranged on opposite sides of thecavity, and wherein the lifting shaft is arranged adjacent and parallelto the first vertical side section and the first pair of lifting bandsextends in a substantially horizontal direction from the lifting shafttowards the second vertical side section.
 12. A container-handlingvehicle according to claim 1, comprising at least two adjacent liftingdevices.
 13. A storage system comprising: a three-dimensional grid andat least one container-handling vehicle according to claim 1, whereinthe grid comprises multiple storage columns, in which storage containersmay be stored on top of one another in vertical stacks, and thecontainer handling vehicle is operated on rails at a top level of thegrid for retrieving storage containers from, and storing storagecontainers in, the storage columns, and for transporting the storagecontainers horizontally across the grid.
 14. (canceled)
 15. (canceled)